Cigarette filters and method of making same



Oct. 4, 1960 H. A. LEBERT 2,954,773

CIGARETTE FILTERS AND METHOD oT MAKING SAME Filed Jan. 23. 1958 J /f fhf4 L im 'f 7 TRL-:Lm fllllllllllllli/ 2,954,713 CIGARETTE FILTERS MnrnonoF MAKINGSAME Herbert A. Lehert, .Millbrae, Calif., assignor to Mac-Farland, Aveyard Company, Chicago, Ill., a cor- `poration of Delaware,Filed '1mb 2.3., IV19.5.8., Ser. No. 710,180

9 claims. (ci. rs1- 1.0)

The present invention relates lgenerally to .cigarette structures land amethod kof manufacturing .the same. More specifically, the j presentinvention relates to a Ifilter tip construction 4and the vmethod ofmanufacturing the same whereby the filter tip is provided with a venturipassageway area intermediate its length so that the velocity of smokepassing through the `filter tip may be accelerated and tars in thesmokemay Abe imp'inged upon fibers of the filter tip in a new and improvedmanner.

The majority of .present day filter-,tip cigarettes use cellulosefilaments in varying amounts with various binders and additives.However, in spite ,of lthe manly athousands of fine filaments, thefilter tips still have .considerable I space` between the filaments ifora LrV16" -diameter filter tip bc compressed 'into a 1/s diameter rod orbundle, `that is, a reduction in crossfsect'ional area from approxinrately .07 square inch to .01 square inch or `the equivalent of an-air'passage of approximately .06 squareI inch .or li/gg diameter. Sucha large Vair passage in marked con- '-tra'st to the l@ inch or lessorifice used to create high velocity-'impingement tar collectionaccording to the principles of my invention as set forth in my earlierfiled compending application. In this respect, the present applicationis a continuationinpart lof my copending applif cation, vSerial No.662,049, filed May 28, 1,957, for Removal of Tar and Other DeleteriousSubstances From TobaccoiSrnoke.

It is clear that the conventional filter tips trap -Or col lect such taras they do stop by virtue of the maze formed by the filaments and thecircuitous path the smoke `travels in passing along the length(approximately %6) of the filter tip.

In contrast to the above conventional filter tips ythe same fibrousstranded or cellulose stranded filter tip can be made to `function as aVenturi-impingement tar re-A mover by constricting a narrow zone orsection of the filter tip according to certain principles of my'invention in the present application lso that the aggregate of the airlspaces left through the constricted areaor zone will approximate a ggdiameter hole. Then as smoke is drawn through the constricted area orzone it will vbe greatly accelerated and then impinged on the kbarrierformed by the relatively loose packed filament confrontingly .disposeddownstream thereof with the tars thereby being extracted.

According to the pres-ent invention the principal object is to' form acritical -s'ized smoke passage or venturi which will speed up ytheLsmoke `to a terrific velocity exceeding, e.g., onehundred feet persecondso that the heavy (high temperature formed) .tar molecules orparticles will not be able to meander their lway through the remainingrelativelyr loose packed strands o-f lfilter material', but will,instead, irnpinge against and come to rest on the strands or.filamentsof filter tip material that confront or stand in their high speed,straight line path from the'venturi passage. 'Ihe lighter weightaromatic, low temperature -formed smoke particles or fractions whichgoto make up a safe, enjoyable smoke will change their high speed '2straight line path to conform to .thedeviousgpaths formed by .the spacesbetween vthe relatively loosely packed Llilaments that make up theilter'tip.

Expansion cooling of tobacco smoke requires Yan elongated expansionchamber for the smoke toexpand which 4structure is conventional in theAccording to -the present invention .the .manufacturing cost .of .thefilter tip may be kept to a minimum since the expansion .chamber is notrequired `and Vthe dimensions ofthe ,conventional v.filter tips ma-yremain substantially unaltered .despite .the inclusion .of .the critical`passage area. lAnother advantage of the present invention is that astandard, .conventional filter tip may be utilized `and its method ofmanufacture may vbe varied only slightly `so as .toincorporate in Ytheconventional filter tipy the critical .passage iarea as noted above.

l.If the conventional filter tip is Aprovided with a venturi passageway,area according to Ythe principles of the present invention before it isattached wit-h the cigarette proper, the attaching wrapper or paper willhide the construction so that the finished cigarette will 1appearidenti, cal to a conventional filter tip cigarette. This resemblance inappearance is the only similarity, however, since `upon being testedby'the smoker the improved taste will be immediately noted and 'if ,thefilter tip is brokenopen after the cigarette has been smoked, the reasonfor the improved smoke will also be readily apparent in thesubstantially increased amount of tar accumulation therein.

If the 'filter tip construction 'is manufactured with an ai-r passagearea, for example, equivalent to yan .028- .030" diameter hole, all thetars regarded harmful by modern medical thinking will be deposited thatis., im` pinged on the filter tip filaments.

The present filter tip construction when comprised of some suitablesubstance such as cellulose has between its opposite ends anvintermediate fused area with the opposite ends being linked by .thecritical vpassageway area through the intermediate fused area. Thefilter tip fibers downstream o-f the passageway operate as animpingement barrier against which the smoke strikes at velocitiesexceeding feet per second after passing through the criticallypassageway area.

The filter-tips may be provided with the critical passageway area by,for example, hot rolling the intermediate portion of the filter tipblank causing the diameter to'be reduced and with the heat fusing thecellulose fibers.`

Accordingly, an object of the present invention is to provide a new andimproved highly economical method of manufacturing filter tip elementsand filter tip cgarettes.

Still another object of the present invention is to' provide a new andimproved filter tip construction which is highly economical.

Yet another object of the present invention is to provide a filter tipconstruction and method of manufacture which may be carried out so as toenable efficient large scale mass production of the same'.

Other objects and features of the present 'invention will more fullybecome apparent in View of the following detailed description taken inconjunction with the accompanying drawings illustrating therein a singleemmodiment and in which:

.Figure l is a fragmentary cross-sectionall schematic View of my methodof manufacturing filter tips for cigawt-tes;

Figure 2 is an enlarged fragmentary crosssect'ional view, partially inelevation, of a fibrous length of filter tip material as shown in Figure1;;v

Figure 3 lis "an, enlarged fragmentarycross-s'cctioirala view takensubstantially on the line III-III; of Figure looking in the directionindicated'by the. arrows Figure 4 is an enlarged fragmentarycross-sectional view of a lter tip according to the principles of thisinvention;

Figure 5 is an enlarged cross-sectional View taken substantially on theline V-V of Figure 4 looking in the direction indicated by the arrows;and

Figure 6 is an enlarged cross-sectional view similar to Figure 4 onlyillustrating the filter tip in assembly with tured from any suitablematerials such as cellulose, other fibrous materials, and Ithe like. InFigure l a mass of fibrous material 12 is disposed upstream of anextruder mechanism 13 with the fibrous material being actuated or forcedthrough the extruder mechanism 13 in a manner whereby a length or strip14 of fibrous materials such as cellulose is extruded which strip has areduced crosssectional dimension.

' Downstream of the extruder 13 is a mechanism 15 for reducing thecross-sectional dimension ofthe strip 14 at predetermined instancesalong the length of the strip. In the illustrated form the mechanism 15is suitably shown as a roller ymechanism including rollers 15a and 15bwhich are preferably heated along with a roller mechanism portion 15ewhich serves to support the rollers 15a and 15b. This heated rollermechanism serves to constrict the diameter or" the strip and operates tofuse predetermined areas on the strip of material as will hereinafter bedescribed in further detail.

The extruder 13 has a bell-shaped passageway 13a and a spider 16 ismounted within the reduced diameter area of the passageway which spider16 supports a wire 17 of predetermined critical size.

VEach filter tip includes opposite end portions a and 10b which areseparated from one another by an intermediate fused portion 10c whichhas a reduced crosssectional dimension or area as compared to theopposite end portions 10a or 10b. Extending longitudinally of thereduced intermediate fused portion 10c is a longitudinal passageway areaor passage 10d which passage allows smoke to passfrom the upstream end10b of the filter tip to the downstream end 10a and then into the mouthof the smoker. The opposite end portions 10a and 10b each have annularperipheral fused areas 10e which Voperate to confine the smokeinternally of the fused area 10e of the filter tip 10.

Each Vof the opposite end portions 10a and 10b is comprised of amultiplicity of fibers 107 with the fibers on the downstream side of thepassageway 10d providing an impingement ba-rrier for the accumulation oftar particles as indicated at T in Figure 6.

According to the method aspects of the present invention, the extrudermechanism operates to extrude a stream or strip of fibrous materialhaving aninternal longitudinally extending passageway 14a created by thewire or rod 17. As the strip of material passes from the extruder rollermechanism 15 constricts the strip forming annular grooves or depressions.leb therein. By virtue of the fact the roller mechanism is heated theperipheral areas of each strip segment 14C is fused. Also, since theroilers 15aF are heated and further since the rollers operate toconstrict the material between the segments 14e, link strip portions 14dare internally fused throughout except the area where the passageway 14aextends longitudinally therethrough. Y

Downstream of the extruder mechanism 15 is provided a cut-off mechanism18 which mechanism operates to cut each of the strip segments 14C inhalf. It will .be noted the terminal end of the `wire or rod`17V isdisposed up-Y n locity of the smoke passing through theffilter tip may 4stream of the cut-o mechanism 18 to avoid interference therewith. ItWill also be noted that since the brous material remains in a flexiblerelativelyspungy state after each filter tip 10 has been cut from thestrip, the portions of the passageway 14a extending the length of thestrip sections 14C, or the opposite filter tip end portions 10a and 10b,are closed. i Since the intermediate linking portion of the lter tip isfused, the longitudinal passageway 10d remains therethrough after thefilter tips 10 have been cut from the strip 14. I Each of the iiltertips 10 is preferably peripherally sealed in order to preclude the smokefrom bypassing the longitudinal passageway 10d and jumping across thegap between the opposite end portions 10a and 10b at the outer peripheryof the reduced diametered area 10c. As has beeny discussed above, thefilter tip 10 may be heat glazed to fuse the peripheral surface or theperipheral surface of `each of the filter tips may be provided with acoated seal such as by spray painting or the like. In `any event, thelinking or intermediate portion 10c should be preferably substantiallysolid except for the passageway area 10d extending therethrough so thevebe effectively increased.

Each of the filter tips may be suitably provided with a peripheral layercomprised of paper or some :other suitable material which layer isindicated generally at 19 in Figure 6. The peripheral layer 19 asillustrated comprises a tubular member and extends across the depressedarea ofthe filter tip so that the iilter may have ya conventionaltubular appearance. Eachof the lter tips is then abutted against acigarette 20 and a paper piece 21 is wrapped around the periphery of thefilter tip 10 and the cigarette 20 to connect them together (Figure 6).

In the past, the problem presented has been one of providing sufficientsmokeV flow to satisfy the smoker while at the same time removing thedeleterious tars,y etc. In the structure of the present invention, thisproblem is overcome by providing a venturi orilice or passageway whichgreatly increases the velocity of the smoke stream passing through theiilter tip so that when the stream strikes the barrier comprised of amultiplicity of fibrous Strands such as cellulose, the tar is lodged andcollected upon the peripheral surface of the fibrous strands and theresulting purified smoke alters its course through the strands andpasses onto the smoker through the downstream end 10a of the filter ytip10. By referring to the removal of tars the termftars should be regarded`as embracing tars, resins, and other harmful substances. While therewill be variations in the size of the orifice, depending upon thecharacter of the smoke, the density of the cigarette mass, etc.,in'general eii'ec-` tive results are obtained where the orifice diameteris from .025 to .038 (square inch areas of .0005 to .001). Verysatisfactory results have been obtained where the orifice diameter is.028" to .032 (.0006 to '.0008 square inch). As a preferred example, Ihave` employed effectively an orifice having a diameter of .030 (.0007square inch), which gives excellent tar removal and ease of drawing. f

i The operation resulting from the structure shown herein is in contrastto the operation of cooling devices heretofore employed with cigaretteswhere arelatively large `expansion chamber is required. Such coolingdevices bring about a peripheral cooling of the smoke but allowsubstantial core portions of the tars to pass onto the smoker withoutthe tars being removed therefrom. In the present structure, the entirecross-section of the smoke stream is subject to the action of theimpingement barrier comprising the downstream end 10a of the lter tip sothatthe Vtars and other harmful particles are removed by the foregoinghigh velocityimpingement action upon the barrier.

The passageor orifice is effective in greatly increasing the-velocity ofthe smoke so that it is substantially in excess of 100 feet per second.If more than one orice is used the total square inch area should fallwithin the range given. In this case the method of manufacture may bealtered since one or more additional wires may be sustained within thestream of lter tip material in the formation of the orices or passagesin the intermediate fused area c to enable the square inch area to fallwithin the range given. Of course, the velocity will vary considerablywith different smokers and cigarettes of varying degrees of density. Bypositioning the barrier in confronting relation to the outlet of theorice, the attained high velocity is effective in lodging the tarfractions directly upon the strands of lter tip material therebyremoving them from the smoke.

It will be understood that modifications and variations may be effectedwithout departing from the scope of the novel concepts of the presentinvention.

I claim as my invention:

1. A method of manufacturing lter tips for cigarettes comprisingextruding a length of cellulose bers, at selected intervals reducing thediameter of localized areas along the length of cellulose bers bycompacting the cellulose bers and fusing the compacted cellulose berstogether at the localized area, where the diameter has been reducedforming therethrough a venturi passageway of about .025-.038" diameter,and dividing the length of cellulose fibers into a series of filter tipsfor cigarettes e'ach having one of the venturi passageways.

2. A method of manufacturing filter tips for cigarettes comprisingextruding a stream of cellulose bers, at selected intervals reducing thediameter of localized areas along the stream of cellulose bers bycompacting the cellulose bers while contemporaneously setting upinternal forces resisting compaction centrally of the stream and fusingthe compacted cellulose bers together at the localized area where thediameter has been reduced, forming a venturi passageway having .025".038diameter through the localized area where the diameter has been reduced,and dividing the stream of cellulose bers into a series of lter tips forcigarettes each having one of the venturi passageways.

3. A method of manufacturing lter tip cigarettes comprising reducing thediameter of a -length of brous material by compacting the brous materialconstituting a lter tip providing a smoke impervious localized areaalong the length thereof, contemporaneously setting up internal forcesalong the length of the area being compressed resisting compression andthereby forming a longitudinal venturi passageway of about .028 to .030inch diameter extending longitudinally through said localized area ofthe filter tip for conning a smoke stream to travel at high Velocitytherethrough, assembling the filter tip and a cigarette in end-to-endrelation, and Wrapping a length of material about the filter tip and thecigarette connecting them together in assembly.

4. A lter tip for cigarettes comprising a strip having `an intermediatesmoke impervious portion and opposite peripherally sealed centrallyporous upstream and downstream brous end portions on respectivelyopposite sides of the intermediate portion, and said smoke imperviousportion having a single venturi passageway extending longitudinallyacross the smoke impervious portion linking the brous end portions andof about .025 to .038" diameter and with the venturi passagewayoperating to accelerate the smoke velocity in excess of 100 feet persecond during drawing of smoke therethrough.

5. The lter tip for a cigarette comprising a length of cellulose bersnormally related for passage of smoke uniformly throughout its lengthlongitudinally therethrough and with the fibers in a limited areaintermediate the length of the filter tip being fused together forthereby providing a fused restriction separating respective unfusedportions of the bers on longitudinally opposite sides of thev fusedrestriction, and said fused restriction having a single orice passagewayextending therethrough for passage of smoke, said orice passagewayhaving a square inch cross-sectional flow area of .0005 to .001 foraccelerating smoke to pass through the orice passageway at velocitiesexceeding feet per second during drawing of smoke therethrough, so thattars in the smoke will be impinged upon the unfused bers downstreamadjacent to said orice passageway.

6. A yfilter tip as dened in claim 5 comprising in combination therewitha cigarette joined end-to-end thereto, said lter tip having about saidfused restriction an annular radially outwardly opening depression, anda wrapper about the periphery of the filter tip and a portion of thecigarette joining them permanently together and concealing said annulardepression.

7. A lter tip for a cigarette comprising a length of cellulose fiberswith the bers in a limited area intermediate their length beingcompressed and fused together and with a smoke passageway through thefused bers linking opposite end portions of the filter tip and providinga single hole having a diameter approximating .025"- .038 diameter.

8. In combination, a cigarette and a lter tip in assembly therewith andwith the filter tip comprising a length of brous material having a totalobstruction intermediate its length except for a single venturipassageway therethrough and with the length of brous material includinga brous area on the downstream side comprising an impingement barrier,said venturi passageway being dimensioned for smoke passage therethroughat a velocity in excess of 100 feet per second against the impingementbarrier to remove the relatively heavy tars contained in the smokeimpinged upon the impingement barrier therebyremoving them from thesmoke stream.

9. A method of manufacturing a filter tip for cigarettes comprisingreducing the diameter of a length of brous material and thereby bycompacting the fibrous material providing a smoke impervious localizedarea along the length thereof, contemporaneously setting up internalforces along the length of the area being compressed resistingcompression thereby forming a longitudinal venturi passageway extendinglongitudinally through said localized area of the filter tip for conninga smoke stream to'travel at high velocity therethrough and sizing saidpassageway to a cross-sectional fiow area approximating .025"-.038"diameter.

References Cited in the le of this patent UNITED STATES PATENTS 987,359Gueniffet et al. Mar. 21, 1911 1,555,320 Weil Sept. 29, 1925 1,616,851Geisler Feb. 8, 1927 1,983,926 Zirmer Dec. 11, 1934 1,989,130 Brown Ian.29, 1935 2,246,929 Seney June 24, 1941 2,349,551 Helm May 23, 19442,511,898 Brothers June 20, 1950 2,705,013 Brothers Mar. 29, 19552,769,533 Booth Nov. 6, 1956 2,794,480 Crawford et al. Jan. 4, 19572,780,573 Davidson Feb. 5, 1957 2,820,460 Bunzl lan. 21, 1958 2,869,883Dunbar Jan. 20, 1959 FOREIGN PATENTS 188,091 Germany Ian. 27, 1907

1. A METHOD OF MANUFACTURING FILTER TIPS FOR CIGARETTES COMPRISINGEXTRUDING A LENGTH OF CELLULOSE FIBERS, AT SELECTED INTERVALS REDUCINGTHE DIAMETER OF LOCALIZED AREAS ALONG THE LENGTH OF CELLULOSE FIBERS BYCOMPACTING THE CELLULOSE FIBERS AND FUSING THE COMPACTED CELLULOSEFIBERS TOGETHER AT THE LOCALIZED AREA, WHERE THE DIAMETER HAS BEENREDUCED FORMING THERETHROUGH A VENTURI PASSAGEWAY OF ABOUT .025"-.038"DIAMETER, AND DIVIDING THE LENGTH OF CELLULOSE FIBERS INTO A SERIES OFFILTER TIPS FOR CIGARETTES EACH HAVING ONE OF THE VENTURI PASSAGEWAYS.